5-hydroxytryptophan (5-HTP) is an amino acid that occurs naturally in the body and is the final step in the production of the neurotransmitter serotonin, an important chemical that's responsible for many of the brain impulses involving satisfaction and well being. 5-HTP is created through the hydroxylating of Tryptophan. Tryptophan is an essential amino acid that must be taken in through protein containing foods since the body can not synthesize it. Of the eight essential amino acids, tryptophan is the least common, accounting for only about one percent of protein content, and it is used up rapidly by the body. About ninety-percent is used in protein synthesis. The rest is divided between serotonin production and niacin production, which requires 60mg for every 1mg of niacin produced. However, 5-HTP is only used in serotonin production. 5-hydroxytryptophan is also able to pass through the blood-brain barrier easily, unlike tryptophan, which can only pass through the barrier by using the same transport molecule that caries leucine, isoleucine, and valine.

Unlike tryptophan supplements, 5-HTP supplements are not produced commercially by the fermentation of bacteria. Instead, it is extracted from the seeds of Griffonia simplicifolia, an African tree that is grown mostly in Ghana and the Ivory Coast. The extraction process uses alcohol and produces an oily solid. The oily extract is then purified into a dry solid. 5-HTP can also be made synthetically in the laboratory. The final product is the same as the one made by the body.

On November 17th, 1989 the FDA recalled all L-Tryptophan supplements. The reason was an increasing worry that the supplements may be causing eosinophilia-myalgia syndrome. A syndrome that is characterized by severe muscle and joint pain, swelling of the arms and legs, skin rash and, sometimes, fever. At the time of this recall, tryptophan was gaining popularity in the treatment of insomnia, depression and obesity (among other uses). Today, 5-hydroxytrptophan is considered a safer and more effective treatment for these conditions.